Safety system for machines

ABSTRACT

A safety system for workpiece-processing machines employs a physical guard which prohibits the operator from gaining access to the work-processing area. Workpieces are transferred from the operator&#39;&#39;s side of the guard to the press side by a workpiecereceiving nest. The nest passes back and forth a short distance through an opening in the guard such that it continually blocks off most of this opening. A transfer device picks up a part from the nest when the nest is on the machine side of the guard and transfers it to the work-processing region of the machine.

Jan. 7, 1975 l. l l

Allette SAFETY SYSTEM FOR MACHINES 3,473,357 10/1969 Jackson 83/545 X 3,726,166 4/1973 83/397 X Primary ExaminerWillie G. Abercrombie Attorney, Agent, or Firm-Bean & Bean [73] Assignee: Weber-Knapp Company,

Jamestown, NY.

July 26, 1973 ABSTRACT [22] Filed:

A safety system for workpiece-processing machines Appl. No.: 382,655

employs a physical guard which prohibits the operator from gaining access to the work processing area.

workpieces are transferred from the operators side of the guard to the press side by a workpiece-receiving nest. The nest passes back and forth a short distance through an opening in the guard such that it continually blocks off most of this opening. A transfer device [56] Referen Cit d picks up a part from the nest when the nest is on the UNITED STATES PATENTS machine side of the guard and transfers it to the workprocessing region of the machine.

2,355,082 8/1944 Kearney et 29/38 A UX 3,074,565 1/1963 Gaitten 83/418 X 17 Claims, 23 Drawing Figures r M, 1.... 1| 11 a m) y n- Iain S Patented Jan. 7, 1975 '7 Sheets-Sheet 2 Patented Jan. 7, 1975 7 Sheets-Sheet 3 Patented Jan. 7, 1975 7 Sheets-Sheet 4 Jan 7, 1975 3,858,472

7 Sheets-Sheet 5 IOU Patented Jan. 7,, 1975 7 Sheets-Sheet '7 Non $3 NV 225 mmw i SAFETY SYSTEM FOR MACHINES BACKGROUND OF THE INVENTION There are a number of machines which require an operator first to load the machine with a workpiece and then to cycle the machine to perform a work operation on the workpiece, and to repeat these operations over and over at a reasonably rapid rate. An ordinary punch press is a good example of such a machine. As is well known, the operators of such machines for one reason or another occasionally may reach into such machines and receive bodily injury as a result.

BRIEF SUMMARY OF THE INVENTION Accordingly, it is of primary concern in connection with the present invention to provide an arrangement and system for feeding successive workpieces to a ma chine of the general character described hereinabove wherein bodily injury to an operator positively is prevented. Basically, the arrangement and system according to the present invention involves the utilization of a positive physical guard which prevents an operator from encroaching upon the work area of the machine, such guard means operating in conjunctionwith a workpiece receiving means which transfers workpieces from the operators side of the guard means to the machine side thereof, and transfer means which picks up a workpiece from the workpiece receiving means and transfers it to the work station of the machine.

With the system and arrangement according to the present invention, the workpiece receiving means or nest operates through a small opening in the physical guard means and irrespective of the position in which it may instantaneously reside, such nest essentially blocks such opening thereby acting in conjunction with the guard means positively to prevent encroachment upon the work station by any portion of the operators body.

In a broad sense, then, the present invention contemplates a system and arrangement for machines which otherwise might be dangerous to an operator in which there is a two stage transfer of a workpiece between a loading station at which the operator places the workpiece initially in position and a work station whereat a machine operation is performed on the workpiece. A physical guard means is interposed between the loading station and the work station positively to prevent encroachment by the operator upon the work station dur ing normal operation of the machine and the final transfer of the workpiece takes place through that region of the machine area which is protected by the guard means.

BRIEF DESCRIPTION OF THE DRAWING FIGURES FIG. I is a horizontal section looking down through a punch press mechanism; a

FIG. 2 is a front elevational view of the assembly shown in FIG. 1;

FIG. 2a is an enlarged elevation showing a modificatron;

FIG. 3 is an enlarged perspective view showing the work receiving portion of the machine as indicated within the area designated in FIG. 1;

FIG. 4 is an enlarged perspective partially broken away showing the clamp mechanism of the work transfer assembly as depicted within the area shown in FIG.

FIG. 5 is an elevational view showing a portion of the work transferring means;

FIG. 6 is a vertical section as taken along the plane of section line 6-6 in FIG. 5; a

FIG. 7 is a side elevational view of the work transfer assembly; a

FIG. 8 is a horizontal section taken along the plane of section line 8-3 in FIG. 7;

FIG. 9 is a horizontal section taken along the plane of section line 99 in FIG. 7;

FIGS. Illa-10f are views illustrating various stages of the cycle;

FIGS. 11a and 11b is a circuit diagram illustrating the cycling control;

FIG. 12 is a plan view of the control console; and

FIG. 13 is a diagrammatic view illustrating a modified cycle.

DETAILED DESCRIPTION OF THE INVENTION With referenceto FIG. 1 the bolster of a press is in: dicated generally by the reference character 10 and upon which is mounted a conventional die assembly indicated generally by the reference character 12 includ- I ing a die member 14 upon which a workpiece is adapted to be received for subsequent operation thereon by the ram 15 (FIG. 2). The region indicated generally by the reference character 16, then, represents the work station of the machine andan operators station is located in the vicinity of the area indicated generally by the reference character l8. Separating the operators station 18 from the work station 16 is a fence or guard means indicated generally by the reference character 20 which, as shown,'may take the form of a series of posts or rods 22 operating in conjunction with a movable guard plate 24 which covers normally substantially the totality of an opening which allows access from the operators station 118 to the work station 16, the guard means positively preventing encroachment by an operator upon the region of the work area 16.

A workpiece receiving means indicated generally by the reference character 26 is movable back and forth. beneath the guard plate 24 through a small residual opening in the guard means 20 and is adapted to effect a first stage transfer of a workpiece from the operators side of the guard means 20 to the work station side of the guard means as hereinafter more particularly described. The secondary workpiece transfermeans is indicated generally by the reference character 28and includes a movable arm 30 carrying mechanism adapted to pick up a workpiece from the means 26 when the same is on the work station side of the guard means 20 and to transfer it then to and upon the die 14- whereaf' ter the assembly 28 and in particular the arm 30 thereof retracts to clear the die area and to permit a subsequent press operation to be performed on the workpiece now received in the die 14. Thus, it will be seen that the system as is generally described above allows an operator to load a workpiece onto the means 26 while at all times being positively prevented from gaining access to the work station area 16 such as might cause bodily injury to the operator. The cycle of operations and the control of the press mechanism may be effectedby a conventional foot switch device and the control system as hereinafter described synchronizes movements of the means 26, the means 28 and of the press mechanism so as to achieve cyclic operations thereof. Workpieces are sequentially placed on the die member 14 and the press performs the work operation thereon whereafter the workpiece is removed from the die 14 and a new workpiece is presented thereto, and so on in a generally normal fashion in which a press of this type would be operated.

It is a feature of the invention that a means 28 is capable of operation in several modes. For example, the

workpiece can be picked up and transferred either by electromagnetic means, by mechanical clamp means or by vacuum pick-up means. Moreover, the operation can be single cycle or automatic cycle and the movements of the arm may either be simply rectilinearly back and forth between the pick-up point and the drop point at the die 14 or the arm may additionally have up and down motions as hereinafter described.

As shown in FIG. 2, the secondary work transferring means 28 includes a mounting base member 32 which is affixed to the bed 34 of the press as by the fasteners 36 and through the medium of an adjustable lead screw member 38, the bracket portion 32 allows vertical adjustment of the slide or way members 40, which slide members 40 allow vertical reciprocation of the base portion 42 of the means 28 as effected under the control of a fluid piston and cylinder assembly 44. The piston and cylinder assembly 44 is rigidly mounted on a base plate 46 which is affixed to the slide members 40 and the piston rod 48 thereof connects to the base member 42 to impart to it the requisite vertical up and down motion as hereinafter described.

Mounted on the base 42 is a bed plate 50 which is guided on the way portion 52 of the base plate 42 for rectilinear movement to the left and right in FIG. 2 under the control of an adjustable lead screw member 54. This allows transverse adjustment of the means 28 and, in particular, of the arm 30 thereof whereby to achieve proper alignment of the arm with the die member14 as will become presently apparent.

Mounted on the bed plate 50 is a frame 56 which, as

can be seen in FIGS. 7 and 8, fixedly mounts a slide bar or rod 58 upon which the arm 30 is bushed or guided as shown clearly in FIG. 8. The outboard side of the arm 30 is provided with a stabilizing roller 60 disposed between a pair of flanges acting as a track. The lower flange is indicated at 62 in FIG. 8 and the upper flange will be seen at 64 in FIG. 7. Fixed to the arm are a pair of motion transmitting rods 64 and 66 which project through the frame 56 and are interconnected at their outer ends by a connector strap 68 which, as will be seen in FIGS. 7 and 9, is connected to the piston rod 70 of a fluid piston and cylinder assembly 72 by means of which back and forth motion of the arm 30 is effected. The piston and cylinder assembly 72 may be mounted on a base member 74 guidably received on a slide portion 76 connected to the frame 56 and provided with a feed screw mechanism 78 thereby to shift the cylinder 72 back and forth as may be necessary and desired.

A motion checking cylinder 73 is also mounted on the member 74 as can be seen more clearly in FIG. 9, same being provided with a piston rod 75 which, like the piston rod 70', is threaded. The piston rod 70 receives the nuts 82 and 84 which sandwich the connector plate 68 and the motion check strap 86 therebetween, as is clearly shown. The piston rod 75 is provided with a pair of stop nuts and 88 against which the strap 86 engages at either end of the stroke of the piston rod 70. The assembly 73 acts in the fashion of a shock absorber to arrest the end-of-stroke movement of the arm 30 and in one mode of operation the assembly first checks the motion of the arm at the die 14 and then allows it to carry beyond this position, the purpose of this function being described hereinafter. Suffice it to say at this point, however, that the cylinder 72 nor mally causes back and forth motion of the arm 30 between two fixed positions at which its motion is checked by the cylinder 73.

As mentioned previously, in some modes of operation, it may not be necessary for any vertical up and down motion of the arm 30 and, in such instances, the arrangement shown in FIG. 2 for the base 40 and its mounting to the bed 34 of the machine may be replaced by the mechanism shown in FIG. 2a. In this instance, the mounting base 42 is rigidly fixed to a member 90 which isslidably engaged in the way plate 92 and may be adjusted to a fixed vertical position by means of the lead screw member 94, the parts 50 and 52 being associated with the base member 42' as previously described.

As is shown in FIG. 4, the outboard end of the arm 30 may be provided with a mechanical clamp assembly indicated generally by the reference character 100. Al though this clamp may take any convenient or desired form, the embodiment shown in FIG. 4 incorporates a pair of clamp jaw arms 102 and 104 respectively connected to the pin member 106 and 108 in the mounting block 110 and a fluid actuator indicated by the reference character 112 is effective to engage the inner end of the arms 102, 104 and move them between the full and phantom line positions as is shown in FIG. 4. A pair of switches 114 and 116 are operatively associated with the arms to detect whether the clamp is in the open or closed position. The arms 102 and 104 are provided with slots 118 and 120 by means of which the movable jaw members 122 and 124 are adjustably positioned thereon so that when, in the closed position, they may effectively engage the workpiece such as that indicated by the reference character W in FIG. 4 and which is the workpiece ultimately to be transferred to the die member 14in FIG. 1.

The work-receiving means 26 can be seen more clearly in FIGS. 3, 5 and 6. As shown in FIG. 6, the work-receiving means 26 is mounted on the bed 34 of the machine through the medium of a mounting plate 120 which is rigidly affixed to the bed 34 and which receives fasteners 122 operating through elongate slots 124 in the mounting bracket 126 so as to permit the requisite vertical adjustment of the workreceiving means 26 as is required for accurate alignment thereof with respect to the die member 14, as will be clearly evident. FIG. 6 also shows the guard plate 24 previously described in conjunction with FIG. 1 and illustrates the opening 130 below the lower edge of this guard plate. It will be manifest from FIG. 6 that the traveling plate portion 132 of the work-receiving means 26 in any position thereof normally blocks substantially all of the opening 130 and positively prevents ingress beyond the guard means by the operator. The mounting bracket portion 126 of the work-receiving means 26 is provided with way members slidably receiving the traveling plate. 132 and a fluid piston and cylinder arrangement 134 has its piston rod 136 coupled through the medium of the pin 138 to the traveling plate 132 so that the cylinder 134 effectively reciprocates the plate 132 back and forth between the loading position shown in full lines in FIG. 6 and the pick-up position shown in phantom lines in FIG. 6 whereby to transfer the workpiece W which has been arranged on the plate 132 by the operator from the loading position to the pick-up position.

As is shown in FIG. 3, the traveling plate 132 is provided with crossing T-slots 140 and 142 whereby the nest member 144 may properly be positioned in mutually orthogonal directions so as to place it, and in particular the workpiece W received by the nest in proper position when the feeder or transfer mechanism is in the phantom line position shown in FIG. 6 so that the secondary transfer mechanism 28 may properly engage and pick-up the workpiece W.

FIG. 11 shows a circuit diagram for controlling the entire operation of the assembly whereas FIG. 12 illustrates a control panel associated with the system. As shown in FIG. 12, there are three selector switches on the panel 150, the single-automatic switch selector 152, the magnet or clamp selector switch actuator 154 and the magnet lift, clamp lift or in line mode selector 155. In addition, there is a cycle stop button 156 which operates the switch 158 of FIG. 11.

In the single mode of the selector 152, the switch arm 160 engages the contact 162 in FIG. 11 whereas in the auto mode of the selector 152, the switch arm 160 is engaged with thecontact 163. In the magnet mode of the selector 154, the switch contacts 164 are closed and the contact 165 are open whereas in the clamp mode of the selector 154, the switch contacts 164 are open and the contacts 165 are closed and, as well, the contacts 166 are closed. When the selector 155 is in the mag lift mode, the switch contacts 167 and 168 are closed whereas when this selector is in the clamp lift mode, the switch contacts 167 and 170 are closed. When the selector 155 is in the in line mode, none of the contacts 167, 168 or 170 is closed.

In the circuitry of FIG. 11, there are a number of actuating solenoids designated by reference characters 180, 102, 184, 106, 188, 190, 192, 194 and 196 corresponding respectively to the following actions:

180 feeder back 182 feeder down 184 feeder up 186 clamp open 188 clamp closed 190 feeder forward 192 check release I94 nest forward 196 nest return Before proceeding further, it should be noted that the control systems for the various piston and cylinder arrangements of this invention and in the specific embodiment as described herein are of the impulse valve type. That is to say, the valve which controls the cylinder 72 to return the arm 30 from the vicinityof the die 14 back to the pick-up point is pulsed into position for this action by the solenoid 180 and does not require that the solenoid remain energized to continue the requisite fluid connection and continued motion of the arm back to its pick-up position. In addition, there are a number of position-responsive switches in the circuitry of FIG. 11 as indicated by the reference characters 200, 202, 204, 206, 208, 210, 212, 124, 216, 218,

220 and 222 which are responsive to the following conditions:

200 feeder forward 202 feeder back 204 feeder down 206 feeder up 208 clamp open 210 clamp closed 2l2 prcss ram return 214 check release 216 check normal 218 No. 2 magnet '22() magnet release Most of these position-responsive switches are associated with the feed mechanism and can be seen in the drawings. For example, the clamp open and clamp closed switches 208 and 210 are the switches 114 and 116 of FIG. 4' and the feeder down and feeder up switches 204 and 206 are shown in FIG. 2.

There are two further position-responsive switches and these are associated with the nest or primary feeding mechanism 26. Such switches are indicated at 224 and 226, the switch 224 being closed when the means 26 is on the operators station side of the guard means and is in the loading position and the switch 226 being closed when the workpiece receiving means 26 is on the work station side of the guard means and in position for pick-up of the workpiece.

For illustrative purposes, the sequencing involved when the selectors 152, 154 and are respectively in the single, clamp and clamp lift positions will now be described in conjunction with FIGS. 10 and 11. As stated before, these positions of the selectors will effect the closing of the switches 165, 166, 167 and and will cause the switch arm 160 to engage the contact 162. The closed switch 166 energizes the set of relays 224 to close the contacts 226 and 228 thereof thereby to energize the sets of relays 230 and 232. The relay sets 224, 230 and 232 establish or break other contacts as will be described as the description proceeds.

Assuming the components to be in the position as shown in FIG. 10a with the machine having been idle or shut down for some time and a part having previously been picked up by the feeder means when the foot pedal is depressed to close the switches 234 and 236, the former will energize the relay 238, and the latter will energize the relay240 due to the fact that the feeder back switch 202 is closed consequently to energize the relay 242 so that its contact 244 is closed. At this time, the contacts 248 and 250 of the relay 242 will be closed and open respectively but since the machine has been idle or shut down for some time, as assumed above, the capacitor 252 which would have been charged during a preceding cycle will have long since drained away through the resistor 254 which bridges it and the same is true for all other capacitors shown except those those which are connected across the power lines at this point in time.

The workpiece transfer means .28 and in particular the arm 30 or feeder will move forwardly toward the press ram due to energization of the solenoid as ef fected by the closing of the switch .254 of the relay 240, see FIG. 10b. When the feeder has reached its forward position, the limit switch 200 'is closed and the relay 256 is energized. Prior to energization of the relay 256 when its switches 258 and 260 respectively were closed and open, the capacitor 262 was charged so that when the relay 256 is energized in response to arrival of the feeder at the position shown in FIG. 10c (switch 200 closed), the capacitor 262 is then discharged.

Recalling that the various relays or relay sets 224, 230 and 232 are all energized, a discharge path for the capacitor 262 is completed through the feeder down solenoid 182 at this time. That is, the contacts 264 and 266 of the relay set 232 are respectively closed and open; the contacts 268 and 270 of the relay set 224 are respectively open and closed; and the contacts 272 and 274 of the relay set 230 are respectively closed and open. Thus, with the contacts 276 ofthe relay 256 being closed because the feeder is in its forward position, the discharge path of the capacitor 262 will be through the contacts 260, the contacts 264, the contacts 272 and the contacts 276 to the solenoid 182 thereby to cause the feeder to move downwardly as indicated in FIG. 100. At this time also, the feeder forward switch 200 is closed and the switches 250 and 248 are respectively closed and open so that the capacitor 252 now becomes charged.

When the feeder reaches its downward limit of movement, the switch 204 is actuated so that the switch arm engages the contact 277. Prior to this time, the capacitor 278 was charged through the switch 204 and the contacts 167 of the selector 155. The switch 204, in responding to the downward limit of the feeder, provides a discharge path forthe capacitor 252 to the clamp open solenoid 186. With respect, to this discharge path, several switch contacts are involved. The contacts 280 and 282 of the relay 230 are respectively closed and open so that the discharge path extends to the arm 284 of a switch actuated by the feeder. The arm 284 is caused to engage the contact 286 when the feeder moves forwardly and is caused to engage the contact 285 when the feeder moves rearwardly or' returns so that, the feeder having been moved forwardly, the clamp open" solenoid 186 is energized by discharge of the capacitor 262. Thus, with all the parts in the position of 'FIG. 10d, the clamp opens to release and place the workpiece on the anvil.

When the clamp opens, the arm 286 of the switch 208 moves out of engagement with the contact 287 and engages the contact 288. Prior to this action, the capacitor 290 was charged through the switch 208 and the switch 165 of the selector 154. Thus, when the clamp opens, the capacitor 290 discharges, both to energize the feeder up solenoid 184 and to energize the feeder back solenoid 180. This latter action will also cause the holder to move forwardly so as to present a new workpiece to be picked up by the feeder. Thus, at

any time up to this point the operator will be able to place the new workpiece on the holder.

To trace the discharge paths of the capacitor 290, it will noted that the, contacts 292, 294 and 2960f the relay set 230 are respectively closed, open and closed, and that the contacts 298 and 300 of the relay set 224 respectively are open and closed. Thus, the discharge path of the capacitor 290 is split through the contacts 292 and 296, the former of which completes the path to the feeder up solenoid 184 and the latter of which proceeds through the contacts 300 to the feeder back solenoid 180. In parallel with the feeder back solenoid are the switches 224 and 226 and the corresponding holder forwar and holder back solenoids 194 and 196. When the holder is forward, the switch 226 is closed and when the holder is in its returned position the switch 224 is closed. Thus, the

feeder back operation at this point in the cycle causes the holder to move forwardly so that the movements of the components as indicated in FIG. 10s.

During this return movement of the feeder as shown in FIG. 10b, it quickly reaches its up position so that the arm 302 of the switch 206 moves from the position of FIG. 11 to that in which the arm engages the contact 304 thus to discharge the capacitor 306. The contacts 307 and 380 of the relay set 230 are respectively closed and open so that the discharge of the capacitor 306 is applied to the feeder back" solenoid 180 and, correspondingly, to the circuit of the holder movement solenoids 194 and 196. At this point in the cycle, however, since the feeder is still moving back and since the holder is also still moving forward (so that both switches 224 and 226 are open) discharge of the capacitor 306 has no effect.

Next, while the feeder is still returning, the holder reaches its forward position and the switch 224 is closed. Then, the feeder reached its back position and the switch 202 is. closed thus energizing the relay 242 opening the switch 250 and closing the switch 248 to,discharge the capacitor 252; Because the contacts 310 of the relay set 232 are open, the discharge path is split through the contacts 312 of the relay 242, which is energized through the feeder back switch 202, and through the press operating relay 256. Thus, the discharge path of the capacitor 252 is to the feeder down solenoid 182 and to the press operating relay 256 so that movement iseffected as in F IQ. 10g. 7

Energization of the relay 256 causes the press ram to cycle. As the press ram descends, the switch 212 is operated to cause its arm 222 to engage the contact 315 thus to charge the capacitor 317. When the ram returns, the switch 212 is returned to the position of FIG. 11 and the capacitor 317 will be discharged either through the contacts 319 of the relay 238 (i-.e., foot pedal not depressed) or through the switch arm (the single mode of operation) when the contacts 319 and 321 of the relay 238 respectively are open and closed (foot switch actuated). In any case, the capacitor, in single mode, will be discharged without affecting the cycle.

At this point, of course, the clamp is still open so that the capacitor 290 will not have been recharged and, in the meantime, the capacitor 314 will have been charged. Thus, when the feeder reaches its down position, the arm of the switch 204 will engage the contact 277 to discharge the capacitor 278 again. This time, however, the switch arm 284 will be in engagement with the contact 285 so that the discharge path is through the contacts 315 of the relay at 230 and the contacts 280 to the clamp closed solenoid 188. It should be noted that the contacts 316 and 318 of the relay set 224 respectively are open and closed while the contacts 320 of the relay set 232 are closed. Thus, when the clamp closes to engage the new workpiece on the holder, the clamp closed switch 210 operates to discharge the capacitor 314 through the contacts 318 and 320 to energize the feeder up solenoid 184, see FIG. 10h.

Now when the feeder, holding the new workpiece, reaches the up position as shown in FIG. 101', the holder will be returned for access by the operator. This is caused by reason of movement of the feeder up switch 206 to discharge the capacitor 306. This discharge path, as described above, is through the contacts 307 to the feeder back solenoid 180. Once again, no feeder back action occurs because the I feeder is already in this position switch 226 is closed and the holder returns as shown in FIG. 101' back to the position of FIG. a.

We are now back to the beginning of the cycle and if the operator continues to keep the foot switch depressed, the next cycle will begin, and so on so long as the foot switch is kept in the depressed or actuated condition. If so desired, the automatic mode may be employed which does not require the operator continually to hold-the foot pedal switch depressed.

In the automatic mode, the selector 152 is positioned to engage the switch arm 160 with the contact 163 and to close the switch 330. Thus, as soon as the foot pedal is depressed to energize the solenoid 238, a holding circuit for this solenoid is established through the closed switch 330 and the now closed contacts 332 of the relay 238. The cycle starts and continues as described above except that during the press ram cycle when the switch 212 is actuated, the charge placed on the capacitor 317 is not dissipated. Instead, after the feeder returns (FIG. 10g) and the relay 242 is ener gized to close the contacts 244, the press ram will first cycle (capacitor 317 is not charged at this time) and then when the press ram has cycled out so that the ca pacitor 317 is charged and the switch arm 222 now en gages the home contact 334, the capacitor will now discharge and energize the relay 240. During the press ram cycling, the feeder will have descended, picked up a new workpiece and have returned to its up position, FIG. 10a.

From the above, it is believed clear as to how the circuitry of FIG. 11 is operative'to effect the various types of cycles which may be selected. To aid further in this respect, a magnet operation cycle will now be described in conjunction with FIGS. 11 and 13.

In FIG. 13, the feeder arm 30 includes two magnetic pick-up devices 340 and 342. The nest or holder 26 is shown to contain a workpiece W which will be picked up by the electromagnet 340 and deposited on the anvil 14 of the press. The magnetic device 342 will pick up the workpiece W" from the anvil ultimatelyto carry it beyond the anvil l4 and release it as shown. The motion of the arm 30' is a straight rectilinear path back and forth as shown in the full and dashed line positions of the arm 30 in FIG. 13.

Thus, the selector 152 may be either in single or automatic" position; the selector 154 is in magnet position; and the selector 155 is in in line position. If automatic operation is desired, the switch arm 160 engages the contact 163 and the switch 330 is closed, and for the other conditions specified for the selectors 154 and 155, the switch 167 is open, the switch 165 is open, the switch 164 is closed, the switch 168 is open, the switch 170 is open, and the switch 166 is open. Thus, none of the relay sets 224, 230 and 232 is energized and the following contacts thereof not already described are in the normal conditions as shown in FIG. 11;

Relay set 230 contacts 344 closed contacts 346 and 348 open Relay set 232 contacts 350 open Relay set 224 contacts 352 and 354 closed.

check release check normal energize electromagnet 340 energize electromagnet 3 2 dcenergizc both magnets The cycle starts as described above by forward movement of the feeder in response to energization of the relay 240 and operation of the feeder forward" solenoid 190. The contacts 366 of the relay 240 are also closed momentarily so that the relay 361 is energized. The contacts 368 of the relay 3611 are thus closed and a holding circuit for the relay 3611 is established through the contacts 368 and the contacts 370 of the relay 364. The workpiece W is thus held by the arm 30' because the contacts 370 of the relay 360 are held closed.

As the arm 30' moves forward to a position in which the magnet 342 is above the workpiece W in the anvil v14, the check release" switch 214 is closed and the relay 356 is energized. The contacts 372 of the relay 356, in conjunction with the normally closed contacts of the relay 358, form a holding circuit for the relay 356. The contacts 376 of the relay 356 energize the check release,solenoid 192 which allows the overtravel effected by the motion-check otherwise effected by the cylinder 73 (FIG. 9), and the arm 30' is allowed to carry on to the dashed line position shown in FIG. 13. The check normal switch 216 is so positioned that a partial checking of the motion of the arm 30' ocours as the magnet 342 approaches a position over the anvil 14, thereby momentarily allowing the arm to assure proper pick-up by the magnet 342. As the magnet 342 reaches a position in registry over the anvil 14, the check release switch 214 is closed, the check normal switch 216 closes to release the normal checking action of the cylinder 73 and this cylinder causes the arm to complete its full travel. At the same time, the No. 2 magnet switch 218 is closed thereby to ener gize the relay 362, the contacts 378 of which form a holding circuit in conjunction with the contacts 380 of the relay 364, and the contacts 379 of which energize the magnet 342. The motion of the arm 30' then continues until the check normal switch 216 is closed just before the end of its travel, thereby to open the contacts 374 and cause the cylinder 73 again to perform its normal motion-check function. Finally, at the end of the travel as shown in FIG. 13, the switch 221) is closed to energize the relay 364. The feeder forward switch 200 is of course also closed at this time. The contacts 370 and 380 of the relay 364 deenergize the two magnets, the magnet 3411 depositing the new workpiece W on the anvil and the magnet 342 releasing the finished workpiece W" as shown in FIG. 13.

The feeder forward switch 200 performs the function, in the mode being described, of immediately initiating return of the feeder arm 30. This occurs by reason of the fact that the contacts 258 and 260 of the relay 256 now permit the capacitor 262 to discharge directly through the contacts 266 and the feeder back solenoid 180. The next or holder feeds forwardly at this time also because the solenoid 194 is also energized by the capacitor 262. When the feeder returns, the magnet 340 picks up a new workpiece and the press cycles due to discharge of the capacitor 252 caused by closing of the switch 202 and consequent energization of the relay 242. I

The switch 381 functions at this time to cause the nest to return so that the operator may load a new workpiece into it. The switch 381 is actuated in response to cycling of the press and closes momentarily as the press ram descends thereby to energize the solenoid 196 (switch 226 being closed while switch 224 is open). The solenoid 180 is also energized at this time but since the feeder has previously been cycled for return, this has no effect. Instead, the capacitor 317 is discharged to energize the relay- 240 as soon as the switch 244 of the relay 242 is closed and the switch 254 of the relay 240 is thus closed to energize the solenoid 190 which causes the feeder to move forwardly to initiate the next cycle of operations.

The additional contacts 390 and the contacts 392, 394 not previously mentioned are associated respectively with the relay 242 and the relay 256.

A further feature of the invention will be seen from FIG. 11a and involves the normally open switch 343 in parallel with the switch 226. The switch 343 is open so long as the guard member 24 is in its operative position. This guard member is hingedly mounted along its upper edge such that if the operator, while loading the nest, so times the loading or is delayed by difficulty in loading such that the nest begins to move inwardly which could create a pinch point between the next and the guard member 24, the guard member 24 swings inwardly by contact with the operators hand to close the switch 343. The switch 343 as soon as it is closed causes the nest to return to the loading position so that the operator is not pinched.

In the above description of a preferred embodiment of the invention, the system has been shown and described in conjunction with a metal-working press. However, it is to be understood that other and different machines may be benefited by the system disclosed herein. In general, any type of machine that requires and operator manually to load successive workpieces which are subsequently operated upon at a work station where there is danger of injury to the operator can be modified according to the present invention so that the operator may work themachine in complete safety.

What is claimed is:

1. In combination with a machine having a ram and ananvil defining a work station and means for causing relative movement between said ram and anvil from a separated condition to a closed condition and back to separated condition to perform a working operation, and said machine presenting an operators station spaced from said work station;

guard means separating said work station from said operators station for blocking operator encroachment upon said work station and including an opening therein communicating said operators station with said work station;

workpiece receiving means mounted for movement back and forth from one side to the other of said guard means;

shuttling means for shuttling said workpiece receiving means back and forth through said opening to transfer a workpiece loaded on said shuttling means by an operator to the work station side of said guard means, said shuttling means being always disposed at least partially within said opening whereby effectively to block same; and

workpiece transfer means for transferring a workpiece from said workpiece receiving means to said work station when said workpiece receiving means is on the work station side of said guard means. 2. In combination with a machine having relatively movable members defining a work station adapted to be fed intermittently with workpieces from an operators station located adjacent to but in spaced relation to said work station;

guard means interposed between said stations for protecting the operator from bodily injury due to operator encroachment onto the work station, said guard means having an opening through which workpieces are delivered; workpiece receiving means movable back and forth through said opening for transporting a workpiece from the operators station side of said guard means to the work station side of said guard means;

means for shuttling said workpiece receiving means back and forth through said opening between a first position on the operators station side of said guard means in which said opening is essentially blocked by said workpiece receiving means and a second position on the work station side of said guard means inwhich said opening also is essentially blocked by said workpiece receiving means; and

transport means for transporting a workpiece from said workpiece receiving means to said work station when said workpiece receiving means has reached said second position thereof.

3. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprising in combination:

workpiece receiving means movable between a loading position remote from said work station and a transfer position also spaced from said work station for moving a succession of workpieces from a first position to a second position corresponding respectively to the loading and transfer positions of said workpiece receiving means;

transport means for transporting a succession of workpieces from said second position thereof to said work station;

guard means for isolating said work station from said work receiving means and having an opening through which said workpiece receiving means is I movable, said workpiece receiving means effectively blocking said opening both when in said first and said second positions thereof whereby continuously to block said opening; and

control means for actuating said workpiece receiving means and said transport means in synchronism.

4. In combination with a machine as defined in claim 1 wherein said guard means includes a movable portion defining said opening and beneath which said workpiece receiving means moves and including switch means associated with said movable portion of the guard means for returning said workpiece receiving means to said operators station side of the guard means.

5. In combination with a machine as defined in claim 2 wherein said guard means includes a movable portion beneath which said workpiece receiving means moves and including switch means associated with said movable portion of the guard means for returning said workpiece receiving means to said operators station side of the guard means.

6. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprising in combination:

workpiece receiving means movable between a loading position remote from said workstation and a transfer position also spaced from said work station for moving a succession of workpieces from a first position to a second position corresponding respectively to the loading and transfer positions of said workpiece receiving means;

transport means for transporting a succession of workpieces from said second position thereof to said work station;

guard means for isolating said work station from said work receiving means at least when the latter is in said loading position thereof; and

control means for actuating said workpiece receiving means and said transport means in synchronism,

10. A system as defined in claim 9 wherein said con- I trol means includes switch means responsive to movement of said transport means to said work station for operating said first actuating means to move said nest to said pick-up position thereof.

11. A system as defined in claim 8 wherein said con trol means includes switch means responsive to move ment of said transport means to said work station for operating said first actuating-means to move said ne to said pick-up position thereof.

12. A system as defined in claim 7 wherein said control means includes switch means responsive to movement of said transport means to said work station for operating said first actuating means to move said nest to said pick-up position thereof.'

13; A system as defined in claim 7 wherein said control means includes switch means responsive todisposaid guard means including a movable portion be- I neath which said workpiece receiving means moves and including switch means associated with said movable portion of the'guard means for returning said workpiece receiving means to said operators station side of the guard means.

7. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprising in combination:

guard means for isolating an operator from said work station and having an opening therethrough;

a workpiece-receiving nest and mounting means therefor mounting said nest for shuttling movement back and forth through said opening between a loading'position on one side of said guard means whereat the operator loads the nest and a pick-up position on the work station side of the guard means; first actuating means for shuttling said nest back and forth through said opening;

transport means for shuttling back and forth between said pick-up position of said nest and said work station and including pick-up means for picking up a workpiece from said nest and depositing it at said work station;

second actuating means for shuttling said transport means back and forth; and

control means interconnecting said first and said second actuating means for coordinating movements of said nest and said transport means to present a succession of workpieces to said work station.

8. A system as defined in claim 7 wherein said control means is an electrical circuit arrangement including switch means responsive to arrival of said transport means at the pick-up position of said nest for initiating operation of the associated machine.

9. A system as defined in claim 8 wherein said control sition of said transport means at said work station simultaneously to actuate said first and said second actuating means to return said transport means and move said nest to the pick-up position thereof:

14. A system as defined in claim. 8 wherein said control means includes switch means responsive to disposition of said transport means at said work station simultaneously to actuate said first and said second actuating means to return said transport means and move said nest to the pick-up position thereof.

15. A system as defined in claim 14 wherein said control means includes switch means responsive to disposition of said transport means at said pick-up position to operate said first actuating means to move said nest to said loading position thereof.

16. A system as defined in claim 13 wherein said control means includes switch means responsive to disposition of said transport means at said pick-up position to operate said first actuating means to move said nest to said loading position thereof.

17. In a system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to the operator; said system including a physical guard isolating the operator from the work station; said guard including a fixed portion providing an enlarged access opening and hinged plate portion associated with such enlarged access opening and defining a smaller access opening; a workpiece-receiving nest dimensioned to pass through said smaller access opening between the operators side and the work station side of said guard; actuator means for shuttling said workpiece-receiving nest back and forth through said smaller access opening; and safety control means actuated in response to movement of said hinged plate portion for causing said actuator means to retract the workpiece-receiving nest toward the operators station side of the guard. 

1. In combination with a machine having a ram and an anvil defining a work station and means for causing relative movement between said ram and anvil from a separated condition to a closed condition and back to separated condition to perform a working operation, and said machine presenting an operator''s station spaced from said work station; guard means separating said work station from said operator''s station for blocking operator encroachment upon said work station and including an opening therein communicating said operator''s station with said work station; workpiece receiving means mounted for movement back and forth from one side to the other of said guard means; shuttling means for shuttling said workpiece receiving means back and forth through said opening to transfer a workpiece loaded on said shuttling means by an operator to the work station side of said guard means, said shuttling means being always disposed at least partially within said opening whereby effectively to block same; and workpiece transfer means for transferring a workpiece from said workpiece receiving means to said work station when said workpiece receiving means is on the work station side of said guard means.
 2. In combination with a machine having relatively movable members defining a work station adapted to be fed intermittently with workpieces from an operator''s station located adjacent to but in spaced relation to said work station; guard means interposed between said stations for protecting the operator from bodily injury due to operator encroachment onto the work station, said guard means having an opening through which workpieces are delivered; workpiece receiving means movable back and forth through said opening for transporting a workpiece from the operator''s station side of said guard means to the work station side of said guard means; means for shuttling said workpiece receiving means back and forth through said opening between a first position on the operator''s station side of said guard means in which said opening is essentially blocked by said workpiece receiving means and a second position on the work station side of said guard means in which said opening also is essentially blocked by said workpiece receiving means; and transport means for transporting a workpiece from said workpiece receiving means to said work station when said workpiece receiving means has reached said second position thereof.
 3. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprisIng in combination: workpiece receiving means movable between a loading position remote from said work station and a transfer position also spaced from said work station for moving a succession of workpieces from a first position to a second position corresponding respectively to the loading and transfer positions of said workpiece receiving means; transport means for transporting a succession of workpieces from said second position thereof to said work station; guard means for isolating said work station from said work receiving means and having an opening through which said workpiece receiving means is movable, said workpiece receiving means effectively blocking said opening both when in said first and said second positions thereof whereby continuously to block said opening; and control means for actuating said workpiece receiving means and said transport means in synchronism.
 4. In combination with a machine as defined in claim 1 wherein said guard means includes a movable portion defining said opening and beneath which said workpiece receiving means moves and including switch means associated with said movable portion of the guard means for returning said workpiece receiving means to said operator''s station side of the guard means.
 5. In combination with a machine as defined in claim 2 wherein said guard means includes a movable portion beneath which said workpiece receiving means moves and including switch means associated with said movable portion of the guard means for returning said workpiece receiving means to said operator''s station side of the guard means.
 6. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprising in combination: workpiece receiving means movable between a loading position remote from said work station and a transfer position also spaced from said work station for moving a succession of workpieces from a first position to a second position corresponding respectively to the loading and transfer positions of said workpiece receiving means; transport means for transporting a succession of workpieces from said second position thereof to said work station; guard means for isolating said work station from said work receiving means at least when the latter is in said loading position thereof; and control means for actuating said workpiece receiving means and said transport means in synchronism, said guard means including a movable portion beneath which said workpiece receiving means moves and including switch means associated with said movable portion of the guard means for returning said workpiece receiving means to said operator''s station side of the guard means.
 7. A system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to an operator, comprising in combination: guard means for isolating an operator from said work station and having an opening therethrough; a workpiece-receiving nest and mounting means therefor mounting said nest for shuttling movement back and forth through said opening between a loading position on one side of said guard means whereat the operator loads the nest and a pick-up position on the work station side of the guard means; first actuating means for shuttling said nest back and forth through said opening; transport means for shuttling back and forth between said pick-up position of said nest and said work station and including pick-up means for picking up a workpiece from said nest and depositing it at said work station; second actuating means for shuttling said transport means back and forth; and control means interconnecting said first and said second actuating means for coordinating movements of said nest and said transport means to present a succession of workpieces to said work station.
 8. A system as defined in claim 7 wherein said control means is an electrical circuit arrangement including switch means responsive to arrival of said transport means at the pick-up position of said nest for initiating operation of the associated machine.
 9. A system as defined in claim 8 wherein said control means also includes a switch actuated by said transport means when same is at said work station and a capacitor circuit responsive to actuation of said switch for operating said second actuating means to return said transport means to said pick-up position.
 10. A system as defined in claim 9 wherein said control means includes switch means responsive to movement of said transport means to said work station for operating said first actuating means to move said nest to said pick-up position thereof.
 11. A system as defined in claim 8 wherein said control means includes switch means responsive to movement of said transport means to said work station for operating said first actuating means to move said nest to said pick-up position thereof.
 12. A system as defined in claim 7 wherein said control means includes switch means responsive to movement of said transport means to said work station for operating said first actuating means to move said nest to said pick-up position thereof.
 13. A system as defined in claim 7 wherein said control means includes switch means responsive to disposition of said transport means at said work station simultaneously to actuate said first and said second actuating means to return said transport means and move said nest to the pick-up position thereof.
 14. A system as defined in claim 8 wherein said control means includes switch means responsive to disposition of said transport means at said work station simultaneously to actuate said first and said second actuating means to return said transport means and move said nest to the pick-up position thereof.
 15. A system as defined in claim 14 wherein said control means includes switch means responsive to disposition of said transport means at said pick-up position to operate said first actuating means to move said nest to said loading position thereof.
 16. A system as defined in claim 13 wherein said control means includes switch means responsive to disposition of said transport means at said pick-up position to operate said first actuating means to move said nest to said loading position thereof.
 17. In a system for intermittently presenting a succession of operator-loaded workpieces to a work station at which there is inherent danger to the operator; said system including a physical guard isolating the operator from the work station; said guard including a fixed portion providing an enlarged access opening and hinged plate portion associated with such enlarged access opening and defining a smaller access opening; a workpiece-receiving nest dimensioned to pass through said smaller access opening between the operator''s side and the work station side of said guard; actuator means for shuttling said workpiece-receiving nest back and forth through said smaller access opening; and safety control means actuated in response to movement of said hinged plate portion for causing said actuator means to retract the workpiece-receiving nest toward the operator''s station side of the guard. 